[Establishment of an animal model of Capillaria hepatica].

OBJECTIVE: To establish an animal model of Capillaria hepatica. METHOD: Sixteen rats and two cats were infected with the embryo eggs of Capillaria hepatica through mouth. RESULTS: Of 16 infected rats, 2 were negative, 14 were positive with Capillaria hepatica. 2 cats were negative. CONCLUSION: Rats could be used as an animal model of Capillaria hepatica.

An integration of photosynthetic traits and mechanisms that can increase crop photosynthesis and grain production.

The hypothesis we propose is that during photosynthesis the balance between potentially detrimental and beneficial photochemically induced events can be tipped beneficially toward increased photosynthesis and toward increased crop yield. To test this hypothesis a procedure has been devised with the rice plant, Oryza sativa, that has resulted in increasing both canopy photosynthesis and rice grain yield. Two elite rice varieties selected independently in the contrasting environments of either South China or Texas, each with distinct photosynthetic traits, were crossed to produce a hybrid with an increased canopy photosynthesis and grain yield that is regularly 20 to 22% higher than the mid-yields of the parents. The photosynthetic and mechanisms which may contribute to these beneficial results in the hybrid rice are: a reduction of the midday depression of photosynthesis; a rapid development of the canopy for photosynthetic light interception and an increased canopy photosynthesis; increased amounts of carotenoids for the xanthophyll cycle; an increased protection against free radicals induced by paraquat treatment; a 6 to 12 day shorter plant reproductive life cycle; and a 8 to 10 day increase in the longevity of the flag leaf over the parents. While the hybrid rice has successfully integrated these and likely other unknown characteristics to increase both crop photosynthesis and grain yield, we propose that understanding the underlying beneficial photosynthetic mechanisms supporting these crop plant traits is worthy of thorough investigation and application in crop production.

Filariasis and its control in Fujian, China.

Epidemiological survey of filariasis in Fujian Province, China showed that malayan filariasis, transmitted by Anopheles lesteri anthropophagus was mainly distributed in the northwest part and bancroftian filariasis with Culex quinquefasciatus as vector, in middle and south coastal regions. Both species of filariae showed typical nocturnal periodicity. Involvement of the extremities was not uncommon in malayan filariasis. In contrast, hydrocele was often present in bancroftian filariasis, in which limb impairment did not appear so frequently as in the former. Hetrazan treatment was administered to the microfilaremia cases identified during blood examination surveys, which were integrated with indoor residual spraying of insecticides in endemic areas of malayan filariasis when the vector mosquito was discovered and with mass treatment with hetrazan medicated salt in endemic areas of bancroftian filariasis. At the same time the habitation condition was improved. These factors facilitated the decrease in incidence. As a result malayan and bancroftian filariasis were proclaimed to have reached the criterion of basic elimination in 1985 and 1987 respectively. Surveillance was pursued thereafter and no signs of resurgence appeared.

Observations on the clinical manifestations and treatment of an experimental infection with Brugia malayi in man.

This paper reports clinical observations made during experimental Brugia malayi infection in man. This was induced by 52 infective larvae-carrying mosquitoes, Anopheles sinensis. A monkey, Maccaca mulatta, was inoculated with infective larvae from the mosquitoes infected with nocturnally periodic type of B. malayi from patients. Six months later, the monkey became a microfilaria carrier. Nine days later, the subject was experimentally bitten by mosquitoes infected from biting the monkey, with an estimated delivery of over 200 infective larvae. Seven days after the infection, general (but fluctuating) pruritus developed, followed by lymphadenitis and swelling of the hand and forearm, with a mild pyrexia for nearly 3 months. The eosinophil counts continuously increased. There were four separate attacks of lymphangitis. On day 142, microfilaraemia was first detected. After two more weeks, the subject was treated with a total dose of 15 g diethylcarbamazine (DEC) over 30 days. During this period, 28 small tender subcutaneous nodules appeared on his arms. After treatment, microfilaraemia gradually disappeared and the swelling of his arms improved. Three months later, the eosinophil count of his blood returned to normal but some temporary and scattered small pruritic erythematous patches still persisted over his left forearm. Lymphangitis has not recurred.

Environmental Responses of the Post-lower Illumination CO(2) Burst as Related to Leaf Photorespiration.

As leaf irradiance is decreased in increments, a single transient CO(2) burst is exhibited by C(3) plant leaves. This post-lower illumination CO(2) burst (PLIB) is sensitive to changes in irradiance, to changes in the concentrations of O(2) and CO(2), and to temperature. Increasing O(2) concentrations above ambient produces a progressively larger PLIB while increasing CO(2) concentrations above ambient produces a progressively smaller PLIB. The PLIB, which exhibits many responses to environment common with other methods for measuring photorespiration and photosynthesis, is proposed as a measure of photorespiration in illuminated leaves of C(3) plants. Although the PLIB cannot be used as a quantitative measurement of photorespiration, we propose that the PLIB is a rapid, easy, relatively inexpensive, nondestructive method for evaluating photorespiration in intact illuminated C(3) leaves in air.

A Transient Burst of CO(2) from Geranium Leaves during Illumination at Various Light Intensities as a Measure of Photorespiration.

A transient CO(2) burst is exhibited by irradiated leaves of the C(3) plant geranium (Pelargonium X hortorum, Bailey) after the irradiance is quickly lowered. The light CO(2) burst appears to be related to photorespiration because of its irradiance dependency and its sensitivity to other environmental components such as CO(2) and O(2) concentration. The term post-lower-irradiance CO(2) burst or PLIB is used to describe the phenomenon. The PLIB appears to be a quantitative measurement of photorespiration with intact geranium leaves. The PLIB has been observed with intact leaves of other C(3) plants but not with C(4) leaves. Therefore, it is proposed that, after maximizing intact leaf photosynthetic rates and leaf chamber gas measuring conditions, photorespiration can be measured with intact C(3) leaves such as geranium as a transient post-lower-irradiance CO(2) burst.